The most detailed call state transition flow for a new outgoing call
would be:
UNKNOWN -> DIALING -> RINGING -> ACTIVE
But, if the modem doesn't support reporting intermediate states
(e.g. DIALING or RINGING) then a successful start() should imply
getting into ACTIVE state right away.
For now, only the Huawei plugin implements the detailed transition
support, so make them configurable via call object properties.
Aleksander Morgado
0090124ec0